Abstract: A computer-implemented method comprising: receiving a user-generated request comprising functional data; retrieving a list of data items and a set of dependency rules, each data item being assigned an undefined binary validity value; generating a directed graph by organizing the data items in accordance with the retrieved dependency rules; applying a filtration process to solve the directed graph comprising: calculating the validity value; propagating the validity values through the graph; and filtering the directed graph by keeping only nodes having a validity value of one; calculating, for each filtered data item, a price; and generating a list of available data items with their price. The node suppression decreases the number of data items for which a price has to be calculated, thereby saving resources and/or decreasing the time needed to resolve the user request.